| Year | Value | | 2022 | 5.7880268784362 | | 2021 | 0.77284437035914 | | 2020 | 4.4641443723286 | | 2019 | 0.97193917541932 | | 2018 | 4.2746219861055 | | 2017 | -1.5370996298085 | | 2016 | 0.79244052523602 | | 2015 | 4.3771266506565 | | 2014 | 1.6819731392566 | | 2013 | 0.22267156462464 | | 2012 | 7.5166236466383 | | 2011 | 2.0292405367826 | | 2010 | -2.0778657464187 | | 2009 | 9.9524229074886 | | 2008 | 10.296975822125 | | 2007 | -8.9747396200927 | | 2006 | 8.0362889795133 | | 2005 | 7.8903656746299 | | 2004 | -5.3554002888482 | | 2003 | -1.7525694124866 | | 2002 | 5.1918189519545 | | 2001 | 12.431286527994 | | 2000 | 3.8226008808631 | | 1999 | -8.0250596272746 | | 1998 | 4.2588511022514 | | 1997 | 5.5722571112533 | | 1996 | 11.330878905728 | | 1995 | 9.2303259976866 | | 1994 | 41.724897236441 | | 1993 | -8.427933486518 | | 1992 | -3.1130306721495 | | 1991 | 3.193874730295 | | 1990 | 0.73828226531094 | | 1989 | -3.6891346044147 | | 1988 | 15.47751765143 | | 1987 | -5.9748427672955 | | 1986 | -13.056572575883 | | 1985 | 5.1539990064582 | | 1984 | 20.250896057348 |
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